A theory of necessary and sufficient conditions is presented, as well as a theory of necessary and sufficient causes and effects, viewed as a particular case of the former. Ambiguities of the terms 'condition' and 'necessary condition' are explored, and a neutral meaning for 'condition' is favoured. The relation between necessary and sufficient conditions and implicative conditionals (including counterfactuals) is also discussed. Two problems of counterfactual theories of causal explanation are indicated, concerning (i) how to account for causes that are (...) not necessary and (ii) how to interpret the counterfactual from the negation of the effect to the negation of the cause. Application of the theory of necessary and sufficient conditions to Euler’s explanation of the Königsberg bridge problem is discussed. The theory of necessary and sufficient causes and effects is then applied to the flagpole shadow explanation and to two biological explanations, one involving a sufficient but not necessary cause and the other a necessary but not sufficient cause. Causes that are neither sufficient nor necessary are also recognized. Finally, a probabilistic approach to causes that are either not sufficient or not necessary is explored, including its application to examples of such cases. (shrink)

Abstract In this paper, I investigate the purported dilemma between a symmetrical conception of time and the denial of what I call Universal Logical Determinateness (ULD). According to the dilemma, the timeless and universal application of logical laws to all propositions necessitates either the view that the past and future are both open, or that they are both closed. My investigation proceeds by way of an assessment of Taylor's argument for fatalism, then of Dummet's presentation and refutation of the fatalistic (...) argument, and finally of Dummet's analogous argument which attempts to prove the possibility of an open past. In all cases, we find that the arguments implicitly rely upon the assumption that there exists a necessary connection between the truth aptness of propositions and the fixity (or non-fixity) of events. I question this assumption and conclude that any argument for the symmetry of time which relies upon it begs the question against the asymmetry of time. (shrink)

Describes the received theory of necessary and sufficient conditions, explains some standard objections to it, and lays out alternative ways of thinking about conditions and conditionals.

Um dos grandes desafios da era da informação consiste em filtrar informações claras, rigorosas e atualizadas sobre tópicos importantes. O mesmo vale para a filosofia. Como encontrar conteúdo filosófico confiável em meio a milhares de artigos publicados diariamente na internet? Para ir ainda mais longe, como encontrar uma introdução a algum tópico com uma lista de referências bibliográficas atualizadas e que seja organizada por um especialista da área? Já que você começou a ler este livro, é provável que tenha ouvido (...) falar em algum momento da Enciclopédia Stanford de Filosofia, disponível gratuitamente na internet desde 1995. A página da Stanford faz exatamente isso. Ela cobre inúmeros verbetes sobre quase tudo em filosofia, oferecendo informação confiável sobre temas como feminismo, filosofia na América Latina, zumbis, metafísica e milhares de outros tópicos. A sugestão típica aos profissionais da filosofia que têm interesse em começar a estudar algum tópico, mas não sabem sequer por onde começar, é procurar pelo verbete relevante da Stanford. Infelizmente, o grande empecilho da página para o nosso contexto é que todos os verbetes estão disponíveis apenas em inglês, algo que cria um obstáculo a inúmeros estudantes e interessados que não dominam a língua. Neste sentido, acreditamos que esta publicação preencha um hiato importante na filosofia brasileira. Embora a filosofia no Brasil tenha se profissionalizado e expandido ao longo dos anos, há ainda lacunas em diversas áreas, e os verbetes foram aqui selecionados cuidadosamente no intuito de preencher ao menos algumas dessas lacunas. Este livro apresenta quatro verbetes cruciais para a filosofia, aqui divididos em quatro capítulos: (1) condições necessárias e suficientes, (2) referência (3) causação e (4) consciência. (shrink)

In conclusion, then, the notion of temporal necessity is certainly queer and perhaps a misnomer. It really has little to do with temporality per se and everything to do with counterfactual openness or closedness. We have seen that the future is as unalterable as the past, but that this purely logical truth is not antithetical to freedom or contingency. Moreover, we have found certain past facts are counterfactually open in that were future events or actualities to be other than they (...) will be, these past facts would have been different as a consequence. God's beliefs about the future are such past facts. Moreover, the effects of actions which God would have taken had He believed differently are also such past facts. Oddly enough, then, virtually any past fact is potentially counterfactually open, and the only necessity that remains is purely de facto. We, of course, do not in general know which events of the past depend counterfactually on present actions, and those cases we do know about seem rather trivial. Our intuitions of the necessity, unalterability, and unpreventability of the past as opposed to the future stem from the impossibility of backward causation, which is precluded by the dynamic nature of time and becoming. But the counterfactual dependence of God's beliefs on future events or actualities is not a case of backward causation: rather future-tense propositions are true in virtue of what will happen, given a view of truth as correspondence, and God simply has the essential property of knowing all and only true propositions. With regard to the future, virtually all facts are counterfactually open, and therefore future-tense propositions are not temporally necessary. Propositions thus move from being temporally contingent to being temporally necessary when all the opportunities to affect things counterfactually have slipped by. Hence, the mere fact that an event is past is no indication that it is counterfactually closed. This is especially evident in the case of God's foreknowledge. If we say that God foreknows that I shall do x and therefore I cannot refrain from doing x, lest I change God's past foreknowledge, we are being deceived by a modality which has nothing to do with my power or freedom. All that is impossible is the conjunction of God's foreknowledge that p and of ~ p; but this modality in sensu composito has no bearing on my ability to act such that ~ p would be true and God would have foreknown differently. Temporal necessity, then, turns out to be only obliquely temporal and modally weak, certainly no threat to freedom or divine foreknowledge. (shrink)

Antecedent-strengthening, a trivially valid inference of classical logic of the form: P → Q ⊨ → Q, has a counterpart in everyday reasoning that often fails. A plausible solution to the problem involves assuming an implicit ceteris paribus qualifier that can be explicated as an additional conjunct in the antecedent of the premise. The qualifier can be explicated as ‘everything else relevant remains unchanged’ or alternatively as ‘nothing interferes’. The qualifier appears most prominently in the context of the discussion of (...) laws in the sciences, where these laws are often expressed with a CP qualifier. From an analysis of the qualifier’s role in the problem of antecedent-strengthening, we can learn more about CP qualifiers in general and in their application to the laws used in the sciences. (shrink)

A monist theory of explanation is one that seeks a common definition for all speech acts answering why-questions. One recent example is the counterfactual theory of explanation, which assumes that an ideal explanation can be characterized by the familiar Hempelian criteria for a scientific explanation plus a certain counterfactual that is supported by the laws mentioned in the explanans. I show that the CTE fails. My discussion leads to a critique of the CTE’s key concept of counterfactual dependence and to (...) the suggestion of an alternative: For an argument to be a scientific explanation, a certain necessary-condition claim must be true. For an answer to a why-question to be an explanation, it must express a certain necessary condition. (shrink)